It is understood by those of ordinary skill in the art that golf clubs are typically classified into three main categories: wood-type golf clubs, iron-type golf clubs and putters. The terms "wood" and "iron" are used to refer to a type of golf club for performing specific functions, and are not used to limit the respective categories to specific materials. In fact, present day wood-type golf clubs, iron-type golf clubs and putters are manufactured using various materials such as wood, iron, stainless steel, titanium, tungsten, aluminum, composites, plastics, ceramics and the like.
In a wood-type golf club head, the bottom wall, also commonly referred to as the sole, can incorporate the many different design philosophies of various designers and manufacturers. Examples of existing sole configurations include soles having a smooth planar surface, a rounded downwardly convex surface, a surface with raised rails, or a surface having one or more recesses. One such design is that of a soleplate comprising a medial ridge extending from the front section of the soleplate near the face to the rear section of the soleplate. The soleplate further comprises downwardly concave recesses in the toe and heel sections, as shown and described in U.S. Pat. Nos. 5,240,252; 5,301,945; and 5,470,069; the complete disclosures of these three patents of which are herein incorporated by reference. This previous soleplate was designed with a medial ridge to ease the club head through the grass or turf prior to impact with a golf ball, while the downwardly concave recesses improved the player's ability to hit a golf ball from various sidehill lies. While this soleplate configuration has been considered successful in improving the playability of golf clubs, it is believed that further improvements to playability can be achieved by further lowering the center of gravity of such a golf club head.